stone_on_the_table_CF

#include<iostream>
using namespace std;
int main(void){
	int a;
	int i;
    int count=0;
	cin>>a;
	char arr[a];
	
	for( i=0; i<=a-1; i++){
		cin>>arr[i];
	}
	for( i=0; i<=a-1; i++){
		// cout<<arr[i]<<endl;
		
		if(arr[i]==arr[i+1]){
			count++;
		}
	

	}
	
	cout<<count<<endl;
	


}